In a triangle A B C ,   r 1 cot A 2 + r 2 cot B 2 + r 3 cot C 2 =

In a triangle ABC, r1cotA2+r2cotB2+r3cotC2=
  1. s
  2. 2s
  3. 3s
  4. s2

Solution

Recall that cotA2=ss-a∆ and r1=∆s-a.

i.e. r1cotA2+r2cotB2+r3cotC2=∆s-a×ss-a∆+∆s-b×ss-b∆+∆s-c×ss-c∆

=3s

Asked in: AP EAMCET 2022 (04 Jul Shift 1)

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